I think this article is not 100%. It's good enough to merit linking to.
Our struggle is not just against the psychopath. It's a little more complicated than that, although this idea helps to illuminate a lot of subjects that would otherwise be obscured.
The author doesn't mention what kind of courage people will display when they believe they are defending their own territory. If you take a soldier across the sea into a foreign land and point out some local and say you want that soldier to kill him, you're going to get a lot of resistance for a lot of hardwired genetic reasons, all of them that make excellent sense. There is in effect no real quarrel to be found there unless you can brainwash the soldier into thinking he is fighting for a reason that when examined will not hold water. Psychopaths need to move human beings around like chess pieces because they think life is a game scored with other people's blood.
On the other hand, when defending their own interests on their own soil, not fighting some war drummed up far away by psychos, people will fight with great courage and tenacity even against overwhelming odds. Even the most undistinguished man will come forward and battle like a tiger to protect his own nation and loved ones. That's why Roosevelt knew it would take a Japanese attack on Pearl Harbor to get America into the war and that is why he engineered it. Just have a look at Franklin Delano Roosevelt's face sometime. Ever see so much sick, loathsome and hideous character in one face? Yet the mass media was able to glamorize this horrible and revolting communist cripple to convince the public he was charming. He always seemed to be gritting his teeth in a rictus of ugly viciousness when photographed. Mugs like that take a lot of propaganda in order to thwart first impressions.